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Planetary Camera problems! Please help!


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Hi,

I've recently purchased a QHY5t Planetary Camera and tried to test it on Jupiter last night. I centred the image in the EP, removed it and added the camera, nothing! The screen was black. Racked up the gain, nothing! Added a 2x barlow, checked the position of the planet, still in the centre, nothing! Added a 5x barlow, nothing!

Pointed it at the moon, at last, light. Couldn't get a decent focus, probably cos it was so bright. Focused best poss then back to Jupiter, centred in EP, added the camera, nothing!

Couldn't find it on the screen for love nor money! Jupiter was as bright as a street light last night. What am I doing wrong?

Gave up and went back to observing.

Any advice would be much appreciated.

Clear Skies

Mark

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What EP did you use to centre Jupiter?

You'll need high mag, at least 5mm to get it accurate.

I usually barlow a 5mm to make sure I am dead centre..

Then (carefully) put just the cam (no barlow) so you can at least see if you are in the ball park.

The main problem I have is accurate focus. Jupiter could be dead centre but if the cam is way out of focus you wont see it... (You should not of had that problem if you first focused on the moon though)

Cheers

Edited by rawhead
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On big defocus it could be invisible on the screen. QHY5t has very small pixels and doesn't need a Barlow, as it will get max scope resolution just above f/10 (so SCT doesn't need a barlow). When you added a Barlow to that cam you oversized the image so much it was unfocusable probably.

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Very likely you were out of focus sufficiently far to make the "donut" of the way-out-of-focus planet invisible. Try it on the Moon, no difficulty finding that ... then fit a parfocalising ring to an eyepiece or the camera so you can get the focus nearly right straight off. Even then getting the little b******d onto the chip isn't always easy ... a very accurately adjusted finder with a respectable magnification (at least 8x) is a great help. Try slewing very slowly up & down, the difference in the weights of the eyepiece vs. camera & cable(s) usually makes the tube droop a bit however carefully you centre the planet in the EP ... don't forget that the illuminated area of the chip is tiny compared with the view in the EP ... some people with larger scopes even have difficulty getting Jupiter to fit onto the chip at longer focal ratios!

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X-haired high mag EP to centre initially, with gain up and a longer than needed exp. It's not likely that the cam will be in focus but possibly a faint dough-nut may be seen.

BUT first -test the cam to make sure you're getting a response from the light

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What EP did you use to centre Jupiter?

You'll need high mag, at least 5mm to get it accurate.

I usually barlow a 5mm to make sure I am dead centre..

Then (carefully) put just the cam (no barlow) so you can at least see if you are in the ball park.

The main problem I have is accurate focus. Jupiter could be dead centre but if the cam is way out of focus you wont see it... (You should not of had that problem if you first focused on the moon though)

Cheers

Hi,

Thanks for the advice. I used a 6mm to get the planet centred.

Is there an EP that could be focused that put the cam focus close?

Thanks

Mark

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X-haired high mag EP to centre initially, with gain up and a longer than needed exp. It's not likely that the cam will be in focus but possibly a faint dough-nut may be seen.

BUT first -test the cam to make sure you're getting a response from the light

I'm getting light as I picked up the moon. Awkward to find a focus though.

I figured once I get the moon I would see Jupiter no problem, but the moon was very bright last night.

Thanks

Mark

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Very likely you were out of focus sufficiently far to make the "donut" of the way-out-of-focus planet invisible. Try it on the Moon, no difficulty finding that ... then fit a parfocalising ring to an eyepiece or the camera so you can get the focus nearly right straight off. Even then getting the little b******d onto the chip isn't always easy ...

I like the idea of parfocalising the camera. I have one or two EP's that are parfocal and like the idea you can swap them out without messing about.

Never heard of a parfocalising ring though, sounds neat. Do you have any experience of it and can you recommend / advise on a set up?

Thanks

Mark

Edited by Specman
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Ever cheaper on Scopesnskies Astroboot!

Yes they were cheap enough on Scope 'n' Skies Astro Boot and even do free postage if you buy three items, except if you live in Orkney! They wanted £10 postage :) for something that cost £1.25 and will post in a A000 Jiffy bag as a letter! :)

I have had this out with them before, I live in Orkney and deliver goods sold from my on-line shop world wide via Royal Mail.

I told them that the Scottish Islands is NOT another country, we have a postcode (well not yet anyway :p)

Anyhow, thanks for the heads up. I didn't mean to rant it just makes my blood boil when people charge excessive postage to Scotland.

They sell some nice stuff and I've lost count how many times I nearly purchased from them, only to be put off by excess postage. They do themselves no favours!

Clear Skies

Mark

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Yes ... I have a few ... got them from Modern Astronomy (in the UK) they're not expensive either

Got a pack of four from Telescope house in the end along with a Meade illuminated targeting EP, but thanks for the advice.

Modern Astronomy are a good supplier, purchased a lot from them recently.

Thanks to everyone for all your help. I will try out all you tips and tricks and come back with a 2nd light report!

Clear Skies All

Mark

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